From Monday, 1,000 visitors paying at any of the sites will be offered the ticket so they can go to three other attractions for free.

Mike Ward, the curator at the Grampian Transport Museum in Alford, is the man behind the idea which aims to boost the group during quieter periods.

He said: “Each venue has just 1,000 tickets, available in various combinations of adult, family and concession and it is ‘first come, first served’.

“This initiative is designed to enable visitors and local people to experience the best that the north-east has to offer and to spread the message that we are incredibly lucky in this region to have so much to see, do and enjoy.

“Despite all the emphasis on the internet through websites and social media, research tells us that the most powerful marketing tool is still word of mouth personal recommendation.

“This ticket is such incredible value that we know visitors will experience much more of the north-east than they might usually, and hopefully will enthuse to others when they get home. It is a limited number offer so I would encourage people to get theirs quickly to avoid disappointment as ours sold in a matter of days last year.”